A retrovirus designated human immunodeficiency virus (HIV) is the etiological agent of the complex disease that includes progressive destruction of the immune system (acquired immune deficiency syndrome; AIDS) and degeneration of the central and peripheral nervous system. This virus was previously known as LAV, HTLV-III, or ARV. A common feature of retrovirus replication is the insertion by virally-encoded integrase of proviral DNA into the host cell genome, a required step in HIV replication in human T-lymphoid cells. Integration is believed to occur in three stages: cleavage of two nucleotides from the 3xe2x80x2 termini of the linear proviral DNA; covalent joining of the recessed 3xe2x80x2 OH termini of the proviral DNA at a staggered cut made at the host target site; repair synthesis by host enzymes.
Nucleotide sequencing of HIV shows the presence of a pol gene in one open reading frame [Ratner, L. et al., Nature, 313, 227 (1985)]. Amino acid sequence homology provides evidence that the pol sequence encodes reverse transcriptase, an integrase and an HIV protease [Toh, H. et al., EMBO J. 4, 1267 (1985). Power, M. D. et al., Science, 231, 1567 (1986); Pearl, L. H. et al., Nature 329, 351 (1987)].
It is known that some antiviral compounds act as inhibitors of HIV and are effective agents in the treatment of HIV and similar diseases, e.g., azidothymidine or AZT. Applicants demonstrate that the compounds of this invention are inhibitors of HIV integrase, probably by inhibiting strand transfer and cleavage activity. The particular advantage of the present invention is specific inhibition of HIV integrase.
Applicants have discovered that certain chaetochromins are potent inhibitors of HIV integrase. These compounds are useful for the treatment of AIDS or HIV infections.
Compounds of formula I, as herein defined, are disclosed. These compounds are useful in the inhibition of HIV integrase, the prevention of infection by HIV, the treatment of infection by HIV and in the treatment of AIDS and/or ARC, either as compounds, pharmaceutically acceptable salts or hydrates (when appropriate), pharmaceutical composition ingredients, whether or not in combination with other antivirals, anti-infectives, immunomodulators, antibiotics or vaccines. Methods of treating AIDS, methods of preventing infection by HIV, and methods of treating infection by HIV are also disclosed.
This invention is concerned with compounds of formula I, combinations thereof, or pharmaceutically acceptable salts thereof, in the inhibition of HIV integrase, the prevention or treatment of infection by HIV and in the treatment of the resulting acquired immune deficiency syndrome (AIDS). Compounds of formula I are defined as follows: 
wherein:
R1 is independently selected from:
(a) hydrogen,
(b) C1-6 alkyl, and
(c) C1-6 alkylcarbonyl-
xe2x80x83at each occurrence;
xe2x80x94Xxe2x80x94 is selected from:
(a) a carbon-carbon single bond, and
(b) an oxygen atom bound to adjacent carbon atoms; and
the dotted line, a, is represents a single bond or a double bond; or a pharmaceutically acceptable salt thereof.
In one embodiment of compounds of the present invention are compounds of structural formula (I) wherein:
R1 is independently selected from:
(a) hydrogen,
(b) methyl, and
(c) methylcarbonyl-
xe2x80x83at each occurrence, or a pharmaceutically acceptable salt thereof.
Compounds representing this embodiment include: 
In one subclass of compounds of the present invention are compounds of structural formula (I) wherein R1 is hydrogen at each occurrence, or a pharmaceutically acceptable salt thereof.
Compounds illustrating this subclass are: 
or pharmaceutically acceptable salts thereof.
Also covered by the present invention are pharmaceutical compositions useful for inhibiting HIV integrase, comprising an effective amount of a compound of this invention. Pharmaceutical compositions useful for treating infection by HIV, or for treating AIDS or ARC, are also encompassed by the present invention, as well as a method of inhibiting HIV integrase, and a method of treating infection by HIV, or of treating AIDS or ARC. This invention also discloses the fungal culture MF6252 (ATCC 74396), Fusarium sp.
The present invention relates to the preparation of compounds of structural formula I comprising:
(a) fermenting a culture of MF6252 (ATCC 74396), Fusarium sp. or a mutant thereof to produce a fermentation broth,
(b) extracting the fermentation broth with an organic solvent,
(c) isolating the compounds of structural formula I.
The compounds of structural formula I are preferably isolated by partitioning the fermentation extract between the organic solvent and water, followed by size exclusion chromatography and normal or reverse-phase chromatography.
When any variable (e.g., X, Y, etc.) occurs more than one time in any constituent or in formula I, its definition on each occurrence is independent of its definition at every other occurrence. Also, combinations of substituents and/or variables are permissible only if such combinations result in stable compounds.
The compounds of the present inventions are useful in the inhibition of HIV integrase, the prevention or treatment of infection by human immunodeficiency virus (HIV) and the treatment of consequent pathological conditions such as AIDS. Treating AIDS or preventing or treating infection by HIV is defined as including, but not limited to, treating a wide range of states of HIV infection: AIDS, ARC (AIDS related complex), both symptomatic and asymptomatic, and actual or potential exposure to HIV. For example, the compounds of this invention are useful in treating infection by HIV after suspected past exposure to HIV by e.g., blood transfusion, exchange of body fluids, bites, accidental needle stick, or exposure to patient blood during surgery.
The compounds of this invention are useful in the preparation and execution of screening assays for antiviral compounds. For example, the compounds of this invention are useful for isolating enzyme mutants, which are excellent screening tools for more powerful antiviral compounds. Furthermore, the compounds of this invention are useful in establishing or determining the binding site of other antivirals to HIV integrase, e.g., by competitive inhibition. Thus, the compounds of this invention are commercial products to be sold for these purposes.
Applicants have discovered that certain chaetochromins, recovered from a fungal culture of MF6252 (ATCC 74396), identified as Fusarium sp. (Ascomycotina, Hypocreales), are useful for inhibiting HIV integrase. The compounds of formula (I) are prepared by an aerobic fermentation procedure employing a novel fungal culture MF6252 (ATCC 74396), identified as Fusarium sp., or a mutant thereof. A mutant refers to an organism in which some gene on the genome is modified, leaving the gene or genes responsible for the organism""s ability to produce the compounds of formula (I) in recoverable amounts functional and heritable.
ATCC Deposit of MF6252 (ATCC 74396), Identified as Fusarium sp.
Before the U.S. filing date of the present application, a sample of MF6252 (ATCC 74396), Fusarium sp., had been deposited at the American Type Culture Collection (ATCC), 12301 Parklawn Drive, Rockville, Md. 20852. The culture access designation is 74396. This deposit will be maintained in the ATCC for at least 30 years and will be made available to the public upon the grant of a patent disclosing it. It should be understood that the availability of a deposit does not constitute a license to practice the subject invention in derogation of patent rights granted by government action.
Characteristics of MF6252 (ATCC 74396), Fusarium sp.
Isolated from forest leaf litter, Te Anau, South Island of New Zealand.
In agar culture MF6252=ATCC 74396 exhibits the following characteristics. Observations of micromorphology were made on 1 week-old colonies grown on SNA unless stated otherwise.
Colonies on SNA (Synthetischer Nxc3xa4hrstoffarmer agar; Gerlach, W. and Nirenberg, H. 1982. The genus Fusariumxe2x80x94a pictorial atlas. Milleilungen aus der Biologische Bundesanstalt fxc3xcr Land- und Forstwirtschaft, Berlin-Dahlem 209: 1-406) at 25xc2x0 C., 12 hr photoperiod attaining 25-26 mm after 7 days, translucent, faintly zonate, mycelium most appressed or submerged, with some scant moist conidial pustules surrounding inoculation point
Colonies on oatmeal agar (Difco Laboratories) at 25xc2x0 C., 12 hr photoperiod attaining 24-25 mm after 7 days, developing pronounced moist radial hyphal strands, floccose to, plumose, with margin even, submerged, with aerial mycelium white to pale peach-colored, Pale Ochraceous-Buff, Light Buff (capitalized color names from Ridgway, R. 1912. Color Standards and Nomenclature, Washington, D.C.), basal mycelium yellowish green, Primrose Yellow to near Olive-Yellow. After one month, strongly radially plumose, zone, white to yellowish green. No growth on oatmeal agar at 37xc2x0 C.
Colonies on potato dextrose agar (Difco Laboratories) at 25xc2x0 C., 12 hr photoperiod, attaining 19-20 mm after 7 days, with wide, submerged or moist margin, quickly developing strong radial, semi-erect hyphal strands, dull peach colored to yellowish green, Light Buff, Napthalene Yellow, buff to dull olive, Cream-Buff to near Yellowish Olive, in reverse.
Conidiophores, conidiogenous cells and conidia are of two different states; an Acremonium-like microconidial state which is the dominant form on SNA; and a macroconidial state which on SNA is restricted to pinnotes in the area immediately surrounding the inoculation point, on other media, e.g. potato-dextrose agar, the macroconidial form is produced throughout the colony.
Microconidial state: Microconidiophores 25-70 xcexcm longxc3x972.5-4 xcexcm wide at the base, septate at the base, rarely 2- or 3-septate, mostly unbranched, tapered upward, straight to slightly geniculate, scattered to densely clustered on both the surface and aerial hyphae, terminating in a cylidrical to flared collarette, with slight periclinal thickening evident on some conidiogenesis cells, enteroblastic, phialidic. Microcondia for the most part distinct from macroconidia, 3.5-6xc3x972-3 xcexcm, narrowly ellipsoidal to allantoid.
Macroconidial state: Macroconidiophores aggregated in pinnotes, consisting of penicillately branched fascicles of conidiogenous cells. Conidiogenous cells cylindrical or tapered apically, without collarettes, sometimes with slight periclinal thickenings at conidiogenous loci, with individual conidiogenous cells up to 35 xcexcm long. Macroconidia 10-50 xcexcmxc3x973.5-5 xcexcm 1-6 septate, predominantly 3-septate, fusiform curved, with apical cell rounded, with slightly pedicellate foot cell, often the apical or subapical cells more curved than the more proximal cells.
Chlamydospores and sclerotia not in observed in PDA or OA cultures incubated up to 5 weeks.
This fungus is assigned the anamorph genus Fusarium because it produces moist, fusoid, curved, septate conidia with a pedicellate foot cell from phialidic conidiogenous cells. This isolate possibly belongs in the Section Martiella of Fusarium (as defined by C. Booth. 1971. The genus Fusarium. Commonwealth Mycological Institute, Kew, U.K., pg. 44), due to its abundant Acremonium-like conidial state, penicillate macrocroconidial state, macroconidia with blunt rounded apices, pale to yellow or greenish yellow pigments, and moderate growth rate. The absence of chlamydospores has been noted in some species of the section Martiella e.g. F. illudans and the Fusarium state of Nectria borneensis (Samuels, G. J., Y. Doi, and C. T. Rogerson. 1990. Memoirs of the New York Botanical Garden 59: 47-48).
In general, MF6252 (ATCC 74396), identified as Fusarium sp. is cultured on a solid medium, or in an aqueous nutrient medium containing sources of assimilable carbon and nitrogen. For example, the cultures can be grown under submerged aerobic conditions (e.g., shaking culture, submerged culture, etc.) The aqueous medium is preferably maintained at a pH of about 6-8 at the initiation and termination (harvest) of the fermentation process. The desired pH may be maintained by the use of a buffer such as morpholinoethane-sulfonic acid (MES), morpholinopropanesulfonic acid (MOPS), and the like, or by choice of nutrient materials which inherently possess buffering properties.
The preferred source of carbon in the nutrient medium are carbohydrates such as glucose, xylose, galactose, glycerin, starch, sucrose, dextrin, and the like. Other cources which may be included are maltose, rhamnose, raffinose, arabinose, mannose, sodium succinate, and the like.
The preferred sources of nitrogen are yeast extract, meat extract, peptone, gluten meal, cottonseed meal, soybean meal and other vegetable meals (partially or totally defatted), casein hydrolysates, soybean hydrolysates, and yeast hydrolysates, corn steep liquor, dried yeast, wheat germ, feather meal, peanut powder, distiller""s solubles, etc., as well as inorganic and organic nitrogen compounds such as ammonium salts (e.g., ammonium nitrate, ammonium sulfate, ammonium phosphate, etc.), urea, amino acids, and the like.
The carbon and nitrogen sources, though advantageously employed in combination, need not be used in their pure form, because less pure materials which contain traces of growth factors and considerable quantities of mineral nutrients, are also suitable for use. When desired, there may be added to the medium mineral salts such as sodium or calcium carbonate, sodium or potassium phosphate, sodium or potassium chloride, sodium or potassium iodide, magnesium salts, copper salts, cobalt salts, and the like. If necessary, especially when the culture medium foams seriously, a defoaming agent, such as liquid paraffin, fatty oil, plant oil, mineral oil or silicone may be added.
As to the conditions for the production of cells in massive amounts, submerged aerobic cultural conditions is one method of culturing the cells. For the production in small amounts, a shaking or surface culture in a flask or bottle is employed. Furthermore, when the growth is carried out in large tanks, it is preferable to use the vegetative forms of the organism for inoculation in the production tanks in order to avoid growth lag in the process of production. Accordingly, it is desirable first to produce a vegetative inoculum of the organism by inoculating a relatively small quantity of culture medium with spores or mycelia of the organism produced in a xe2x80x9cslantxe2x80x9d and culturing said inoculated medium, also called the xe2x80x9cseed mediumxe2x80x9d, and then to transfer the cultured vegetative inoculum aseptically to large tanks. The fermentation medium, in which the inoculum is produced, is generally autoclaved to sterilize the medium prior to inoculation. The pH of the medium is generally adjusted to about 6-7 to the autoclaving step.
Agitation and aeration of the culture mixture may be accomplished in a variety of ways. Agitation may be provided by a propeller or similar mechanical agitation equipment, by revolving or shaking the fermenter, by various pumping equipment, or by the passage of sterile air through the medium. Aeration may be effected by passing sterile air through the fermentation mixture.
The fermentation is usually conducted at a temperature between about 20xc2x0 C. and 30xc2x0 C., preferably 22-25xc2x0 C., for a period of about 14-21 days, which may be varied according to fermentation conditions and scales.
Preferred culturing/production media for carrying out the fermentation include the media as set forth in the Examples.
After growth is completed, the cells are harvested by conventional methods, e.g., centrifugation and filtration, and then extracted with the appropriate solvent, e.g., methylethylketone.
The product of the present invention can be recovered from the culture medium by conventional means which are commonly used for the recovery of other known substances. The substances produced may be found in either or both the cultured mycelium and broth filtrate, and accordingly can be isolated and purified from the mycelium and the filtrate, which are obtained by filtering or centrifuging the cultured broth, by a conventional method such as concentration under reduced pressure, lyophilization, extraction with a conventional solvent, such as methylene chloride or methanol and the like, pH adjustment, treatment with a conventional resin (e.g., anion or cation exchange resin, non-ionic adsorption resin, etc.), treatment with a conventional adsorbent (e.g., activated charcoal, silicic acid, silica gel, cellulose, alumina, etc.), crystallization, recrystallization, and the like. A preferred method is extraction of cultured whole broth with methylethylketone, followed by filtration of the extract through filtering aid such as diatomaceous earth. The methylethylketone layer of the filtrate was separated and concentrated to dryness initially by evaporating under reduced pressure followed by lyophilization. The compounds were finally isolated either by solvent partitioning and crystallization or by preparative HPLC on reversed phase systems.
Compounds of formula (I) may be isolated from the aerobic fermentation of a culture of MF6252 (ATCC 74396), Fusarium sp. A culture of MF6252 (ATCC 74396) is defined as substantially free of its natural soil contaminants and capable of forming compounds of structural formula (I) in recoverable amounts. The culture employed in the present invention should be free from viable contaminating microorganisms deleterious to the production of the compound of structural formula (I). A biologically pure culture of MF6252 (ATCC 74396) may also be employed.
The pharmaceutically acceptable salts of the compounds of this invention include those formed from cations such as sodium, potassium, aluminum, calcium, lithium, magnesium, zinc, and from bases such as ammonia, ethylenediamine, N-methyl-glutamine, lysine, arginine, ornithine, choline, N,Nxe2x80x2-dibenzylethylenediamine, chloroprocaine, diethanolamine, procaine, N-benzylphenethylamine, diethylamine, piperazine, tris(hydroxymethyl)aminomethane, and tetramethylammonium hydroxide. These salts may be prepared by standard procedures, e.g. by reacting the free acid with a suitable organic or inorganic base.
For these purposes, the compounds of the present invention may be administered orally, parenterally (including subcutaneous injections, intravenous, intramuscular, intrasternal injection or infusion techniques), by inhalation spray, or rectally, in dosage unit formulations containing conventional non-toxic pharmaceutically-acceptable carriers, adjuvants and vehicles.
The terms xe2x80x9cadministration ofxe2x80x9d and or xe2x80x9cadministering axe2x80x9d compound should be understood to mean providing a compound of the invention or a prodrug of a compound of the invention to the individual in need of treatment.
Thus, in accordance with the present invention there is further provided a method of treating and a pharmaceutical composition for treating HIV infection and AIDS. The treatment involves administering to a patient in need of such treatment a pharmaceutical composition comprising a pharmaceutical carrier and a therapeutically-effective amount of a compound of the present invention.
As used herein, the term xe2x80x9ccompositionxe2x80x9d is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results directly, or indirectly, from combination of the specified ingredients in the specified amounts.
These pharmaceutical compositions may be in the form of orally-administrable suspensions or tablets, nasal sprays, sterile injectible preparations, for example, as sterile injectible aqueous or oleagenous suspensions or suppositories.
When administered orally as a suspension, these compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may contain microcrystalline cellulose for imparting bulk, alginic acid or sodium alginate as a suspending agent, methylcellulose as a viscosity enhancer, and sweeteners/flavoring agents known in the art. As immediate release tablets, these compositions may contain microcrystalline cellulose, dicalcium phosphate, starch, magnesium stearate and lactose and/or other excipients, binders, extenders, disintegrants, diluents and lubricants known in the art.
When administered by nasal aerosol or inhalation, these compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other solubilizing or dispersing agents known in the art.
The injectible solutions or suspensions may be formulated according to known art, using suitable non-toxic, parenterally-acceptable diluents or solvents, such as mannitol, 1,3-butanediol, water, Ringer""s solution or isotonic sodium chloride solution, or suitable dispersing or wetting and suspending agents, such as sterile, bland, fixed oils, including synthetic mono- or diglycerides, and fatty acids, including oleic acid.
When rectally administered in the form of suppositories, these compositions may be prepared by mixing the drug with a suitable non-initiating excipient, such as cocoa butter, synthetic glyceride esters of polyethylene glycols, which are solid at ordinary temperatures, but liquefy and/or dissolve in the rectal cavity to release the drug.
The compounds of this invention can be administered orally to humans in a dosage range of 1 to 1000 mg/kg body weight in divided doses. One preferred dosage range is 0.1 to 200 mg/kg body weight orally in divided doses. Another preferred dosage range is 0.5 to 100 mg/kg body weight orally in divided doses. For oral administration, the compositions are preferably provided in the form of tablets containing 1.0 to 1000 milligrams of the active ingredient, particularly 1.0, 5.0, 10.0, 15.0. 20.0, 25.0, 50.0, 75.0, 100.0, 150.0, 200.0, 250.0, 300.0, 400.0, 500.0, 600.0, 750.0, 800.0, 900.0, and 1000.0 milligrams of the active ingredient for the symptomatic adjustment of the dosage to the patient to be treated. It will be understood, however, that the specific dose level and frequency of dosage for any particular patient may be varied and will depend upon a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the host undergoing therapy.
The present invention is also directed to combinations of the HIV integrase inhibitor compounds with one or more agents useful in the treatment of AIDS. For example, the compounds of this invention may be effectively administered, whether at periods of pre-exposure and/or post-exposure, in combination with effective amounts of the AIDS antivirals, imunomodulators, antiinfectives, or vaccines, such as those in the following table.
It will be understood that the scope of combinations of the compounds of this invention with AIDS antivirals, immunomodulators, anti-infectives or vaccines is not limited to the list in the above Table, but includes in principle any combination with any pharmaceutical composition useful for the treatment of AIDS.
Indinavir is an inhibitor of HIV protease and is the sulfate salt of N-(2(R)-hydroxy-1(S)-indanyl)-2(R)-phenylmethyl-4-(S)-hydroxy-5-(1-(4-(3-pyridyl-methyl)-2(S)-Nxe2x80x2-(t-butylcarboxamido)-piperazinyl))-pentaneamide ethanolate, and is synthesized according to U.S. Pat. No. 5,413,999. Indinavir is generally administered at a dosage of 800 mg, three times a day.